I usually vacuum the kitchen, the dining room and the living room at the same time. But I don't vacuum the kids' rooms.

I've noticed that the floors that I do vacuum get pretty dirty fairly quickly though, even though we don't wear shoes in the house. Perhaps dirt is getting tracked in from the kids' rooms back into the rooms I've vacuumed? I should probably vacuum all of the rooms at the same time... I usually can't motivate to do the whole house at once though.

When you vacuum your home, do you vacuum the whole house or just a room or two at a time? How quickly do your floors stay clean?